Semiconductor packages typically involve one or more semiconductor dies integrated on a substrate, such as, a glass substrate. Passive components such as capacitors and inductors as well as contact pads may be formed on the substrate. The substrate is then attached to a package base, such as, a printed circuit board (PCB). The substrate may be attached to the PCB by way of Ball grid arrays (BGAs). The BGAs include solder balls which may be utilized for forming the connections and attachment between the contact pads of the substrate and the PCB.
For example, with reference to FIG. 1, a side view of a conventional semiconductor package 100 is illustrated. Package 100 includes a glass substrate 102 with a passive component (e.g., inductor 104) and contact pads 103 attached on a bottom surface of glass substrate 102. The combination of glass substrate with inductor 104 may be referred to as a passive-on-glass (POG) structure. The POG structure of glass substrate 102 and inductor 104 is attached to PCB 108 using solder balls which form BGA 106.
However, ball height control of BGA 106 of POG structures may be an issue for customers that utilize different PCB technologies. For example, the line spacing of a top metal layer of PCB 108 may affect the ball height 111 of BGA 106 after assembly. That is, a smaller line spacing of PCB 108 may result in a higher ball height 111 of BGA 106 as compared to a PCB 108 with larger line spacing, due to a difference in the amount the solder balls of BGA 106 collapse after soldering. With this variation in ball height of BGA 106, so too does the spacing between the passive component (e.g., inductor 104) of substrate 102 and the ground plane 110 of PCB 108. As shown in FIG. 1, the inductor 104 is separated from ground plane 110 by a distance 112. Ground plane 110 is an electrically conductive surface connected to an electrical ground. For example, ground plane 110 may be a large area of copper foil which is connected to the ground terminal (not illustrated) of PCB 108, and serves as a ground or return path for current from the various components integrated on PCB 108. The resultant value (i.e., after assembly of package 100) of the passive component (e.g., inductance of inductor 104 or capacitance of a capacitor) may be dependent on the distance 112 between the passive component and the ground plane 110. Thus, in some implementations, the PCB technology utilized by PCB 108 must be taken into account prior to assembly of package 100 when forming the passive component (e.g., inductor 104) to account for the anticipated distance 112.